Haul trucks used in the mining industry require large tires and these tires are often replaced semi-annually. A typical mining haul truck generally requires six tires that represent a replacement cost of over $100,000 per tire, and are replaced twice annually. Therefore, a single typical haul truck requires a tire replacement expense exceeding $1.2 million annually. In the Powder River Basin of Wyoming, which is mined extensively for coal, there is estimated to be 500 of these trucks. In the northeast corner of Wyoming alone, it is estimated that over 500 million dollars annually is spent on replacement tires.
Discarded and stockpiled tires are an environmental and health risk. They are very heavy (often over 3 tons per tire) and replacement requires expensive “downtime” for the haul truck. The problem is compounded significantly considering the number of these trucks across the country—or world—and the increasing demands placed on natural rubber harvest. As demands upon virgin rubber escalate, alternatives to single piece tires must be developed.
Most extended tire wear systems are known as “retreads” which attempt to adhere a new tread surface to an existing worn tire or carcass. These applications are directed at vehicles that may travel at high speeds on pavement, and are susceptible to failure under high heat and stress. Retention of two-piece tires under flexure, loading, and rotation is a continuing problem.
The information included in this Background section of the specification, including any references cited herein and any description or discussion thereof, is included for technical reference purposes only and is not to be regarded subject matter by which the scope of the invention is to be bound.